This invention relates to improvements in an antenna system including a primary radiator and a reflector.
A conventional antenna system of the type referred to has comprised a parabolic cylinder-shaped reflector and a primary radiator including an array antenna disposed in front of an aperture of the reflector so as to direct a primary radiation pattern to the reflector which, in turn reflects the primary pattern into the desired direction as a secondary radiation pattern. Because of the presence of the radiator in front of the aperture of the reflector, the radiator shades or blocks the central portion of the aperture on the longitudinal axis or in the vertical direction so that the secondary radiation pattern in the horizontal plane has its major lobe decreased in field intensity or level and has its first side lobes increased in field intensity.
With such an antenna system used as a radar antenna, it is apt to be affected by clutter such as ground reflections.
Accordingly, it is an object of the present invention to provide a new and improved antenna system comprising a reflector, a primary radiator including an array antenna disposed in front of an aperture of the reflector, and a means for minimizing or substantially eliminating the influence of the blocking by the radiator on a secondary radiation pattern from the reflector.